Hearing aids of various types have long been known. Some known prior art hearing aids have been formed with a custom exterior shell molded with a cavity therein. The components of the hearing aid can be mounted in the cavity thereby forming a structure which fits comfortably in the ear and in part extends into the user's ear canal.
It has been recognized that mounting the components directly within the custom shell presents test and maintenance problems. For purposes of manufacturing, testing and maintenance, it would be very desirable to be able to remove the interconnected components completely from the custom shell and immediately replace same with a corresponding set. Where the hearing aid is physically built into the custom shell, this is usually not possible.
Modular hearing aid systems are known which include a custom shell with a cavity or region formed therein and a compatibly shaped housing. One such product of this type was marketed in the United States at least as early as 1978 by the Oticon Corporation.
The Oticon system utilized a custom shell and a standard housing which could be releasably locked to the shell. The Oticon system used a different housing for the right ear versus the left ear.
In the Oticon system, after the custom shell had been formed, a vent was created in the shell by drilling the shell material appropriately.
While known prior art modular hearing aid systems provide certain benefits, it would be especially desirable to be able to use the same housing for either a right ear or a left ear. In addition, it would be desirable to be able to form the vent canal as an integral part of the unit during the shell casting process without having to separately drill same.
Thus, there continues to be a need for modular hearing aid systems which provide features and benefits of the type described above not heretofore available in such products.